Despite widespread efforts to make evaluation systems more truthful, most teachers continue to receive good teacher-evaluation ratings—including a handful who probably don’t deserve them, according to a recently released working paper.

The findings largely mirror what Education Week reported in 2013, when the first results from systems retooled in the wake of the federal Race to the Top and No Child Left Behind waiver systems came out. States may have built a better mousetrap, but they haven’t changed the cultural norms at work in schools that can impact how principals and other evaluators assign ratings.

For the study, Matthew Kraft of Brown University and Allison Gilmour of Vanderbilt University collected data from 19 states with revamped teacher-evaluation systems. For a large, unnamed school district, they also collected surveys from evaluators in 2012-13 and 2013-14, asking them to guess the percentage of teachers that would fall into each rating category and comparing those figures that to how the teachers were actually rated. Finally, they interviewed some 24 principals.

Here are the top-line findings.

First, the percentage of teachers rated below proficient was generally quite low, ranging from below 1 percent to about 8 percent. New Mexico, with more than quarter of teachers falling into that category, was a major outlier—and has gotten a lot of pushback from its teachers for the tough grading. Interestingly, the range of performance at the top end was much more spread out. Very few teachers in Georgia or Massachusetts earned their state’s highest rating, but more than half did in North Carolina, Rhode Island, Colorado, and Tennessee.

Second, the evaluators in the large school district were far more likely to perceive weaknesses in teachers than they were to actually give them a low score: In the 2012-13 school year, for instance, evaluators perceived that nearly 27 percent of teachers were below proficient, but only about 7 percent received that score.